Kicking off the Summer movie season this weekend, Iron Man 3 lived up to sky-high expectations with $174.1 million haul. That ranks second all-time behind last year's The Avengers ($207.4 million), and is way up on the previous Iron Man outings. The movie also continues to do phenomenal business overseas, and is on its way to earning well over $1 billion worldwide.Iron Man 3's $174.1 million debut is a huge leap over Iron Man 2's $128.1 million. That's a remarkable achievement given the dodgy history of three-quels—nearly all of them decline from their predecessor—and Iron Man 2's questionable reputation. The main reason for this is simple: audiences viewed Iron Man 3 more as follow-up to The Avengers, which is almost universally beloved, than as a sequel to Iron Man 2.The Avengers was a cultural phenomenon, though, and it took an exceptional marketing effort from Disney to retain so much of that movie's audience. The centerpiece of the campaign was the destruction of Stark's Malibu home, which managed to up the personal stakes while also showcasing some impressive action. The marketing also emphasized Stark's conflict with the elusive Mandarin, which is typically a good strategy with superhero movies (a hero is most interesting when juxtaposed against a strong villain). Add in a marketplace devoid of competition, and this was a perfect recipe for a blockbuster opening.

It's worth noting that the other Avengers follow-ups (Thor: The Dark World and Captain America: The Winter Soldier) aren't going to earn anywhere close to this—from a box office perspective, Robert Downey Jr.'s portrayal of Tony Stark/Iron Man is the cornerstone of the entire Marvel Cinematic Universe, and the entries that don't feature him are going to gross noticeably less.

Compared to The Avengers, Iron Man 3's audience skewed a bit older (55 percent over 25, compared to 50 percent) but was about even gender-wise (61 percent male vs. 60 percent). 3D ticket sales accounted for 45 percent of the weekend, which is noticeably lower than The Avengers (52 percent). Thanks to an increased screen count, though, Iron Man 3's $16.5 million IMAX haul was a slight improvement on The Avengers.

While some fanboys aren't thrilled about the movie's twists, general audiences dug it, giving it an "A" CinemaScore. From here on out, if Iron Man 3 performs like Iron Man 2 it will close with $427 million; if it holds up like The Avengers, though, it could earn over $500 million. While word-of-mouth will be more Avengers and less Iron Man 2, a particularly competitive May could keep it closer to Iron Man 2.

The box office was all about Iron Man 3 this weekend—it accounted for over 82 percent of the Top 12's business—and the rest of the lineup suffered as a result. In its second weekend, Pain and Gain tumbled 63 percent to $7.5 million. Through 10 days, director Michael Bay's poorly-received bodybuilder thriller has earned a modest $33.8 million.

Jackie Robinson biopic 42 had a decent hold, easing 43 percent to $6.06 million for a new total of $78.2 million. Oblivion, on the other hand, got obliterated by Iron Man 3: the Tom Cruise sci-fi adventure plummeted 68 percent to $5.64 million. To date, the movie has earned $75.8 million, and it's on track to be Cruise's latest outing to fall short of $100 million. The Croods rounded out the Top Five with $4.2 million, which is off 37 percent. Through its seventh weekend, the DreamWorks Animation hit has earned $168.7 million.

After an awful start last weekend, The Big Wedding dropped 49 percent to $3.9 million in its second frame. Through 10 days, the poorly-reviewed wedding comedy has earned a terrible $14.2 million. Mud expanded to 576 locations and took seventh place with an estimated $2.156million. With $5.17 million in the bank already, the movie appears on pace to earn at least $10 million by the end of its run. Around-the-World Roundup

While its domestic debut was the big story this weekend, Iron Man 3 is doing even better overseas so far. The movie added $175.9 million from overseas markets, and in just 12 days has already earned over $500 million.

Since opening on Wednesday, the movie has amassed an incredible $63.5 million in China; that's more than recent comic book movies The Dark Knight Rises and The Amazing Spider-Man earned in their entire runs. Other top territories for Iron Man 3 include South Korea ($42.6 million), the U.K. ($38.3 million) and Mexico ($35.8 million). Iron Man 3 should be in for another good outing next weekend, though Star Trek Into Darkness could provide tough competition when it opens in the U.K., Australia, Germany and Mexico. Still, a final total north of $800 million seems like a guarantee now, and it could even match The Avengers ($888 million) eventually.